From the viewpoint that a fuel cell scarcely influences the environment, a vehicle is equipped with the fuel cell. The fuel cell is nota secondary battery, and hence, in order to cope with fluctuation of a load or the like, the fuel cell is usually used in combination with a high-voltage accumulator. The performance of this high-voltage accumulator is known to deteriorate owing to overdischarge or overcharge. In consequence, in order to maintain the performance of the high-voltage accumulator, it is important that the power generation of the fuel cell be brought into an appropriate state in accordance with the situation of the load.
It is disclosed in, for example, Patent Document 1 that when the temperature of the fuel cell lowers in a controller for a fuel cell vehicle, maximum output power tends to decrease, and when the rotation speed of a motor is relatively low, the output of the motor is highly likely to increase rapidly, thereby heightening a possibility of a rapid drop in a system voltage supplied to a PCU under these conditions. Here, it is also disclosed that a driving demand output in response to a torque command is obtained from the rotation speed of the motor and the opening degree of an accelerator, and a motor output limiting start voltage and a motor output limiting end voltage are limited by the temperature of the fuel cell and the rotation speed of the motor, thereby preventing an excess drop in the system voltage. Here, the system voltage is an input voltage to a driving circuit of the motor serving as the load, and is also an output voltage from the fuel cell.
Patent Document 1: JP-A-2006-345651